Study on the change of silicon and phosphorus content in the condensed phase during the combustion of epoxy resin with OPS/DOPO

The residues at different time and position of epoxy resin (EP) were obtained during the cone calorimeter tests. The change of Si and P content in these residues during the combustion was obtained by XPS analysis. The result indicates that the Si content reduces at the beginning of fire and the Si element will accumulate with development of fire. These are caused by that, at the beginning of fire, the molten fragment of EP matrix will move upwards and accumulate, but the Si element does not. With development of fire, the product of interaction between the fragment of OPS and decomposition product of EP begins to migrate upwards and accumulate at the surface. However, the P-containing compounds directly migrated upward with the degradation products. The chemical structures of Si-containing and P-containing compounds during the combustion were investigated by the FTIR and XPS. The interactions between DOPO and OPS in the condensed phase happened during the migration process of Si-containing and P-containing compound in the combustion of EP.